Introduction to Prosthodontics

1. Introduction to Prosthodontics Rola M. Shadid, BDS, MSc,

2. History of false teeth • Replacements of lost teeth have been produced for thousands of years • 1st dentures were 700 BC from ivory & bone • Silver, gold, mother of pearl • In 1774, dentures made from porcelain • The real breakthrough came when vulcanized rubber was discovered

3. History of false teeth • The discovery of acrylic resin is the next major revolution in prosthodontics • Another important milestone in tooth replacement was the introduction of implants.

4. Definitions • Prosthetics: Replacements for missing parts of the human body. • Prosthodontics: The branch of dentistry pertaining to the restoration and maintenance of oral function, comfort, appearance, and health of the patient • Prosthesis: An artificial replacement of absent part of human body

5. Definitions • Dentulous: An individual who has his/her natural teeth present. • Edentulous: The individual who has lost his/her natural teeth. • Depending on the number of teeth missing they may be partially or completely edentulous.

6. Branches of Prosthodontics • Fixed prosthodontics • Removable prosthodontics a) complete denture prosthodontics b) partial denture prosthodontics • Implant prosthodontics • Maxillofacial prosthetics

7. Types of Prostheses • Denture: A prosthesis which replaces the one or more teeth and related structures in the mouth. Partial, complete, fixed or removable. • Partial denture: A dental prosthesis which restores part not all of the dentition. • Fixed partial denture: luted or securely retained to natural teeth, roots, or dental implants. The patient cant remove from the mouth.

8. Types of Prostheses • Removable partial denture: Any prosthesis that replaces the teeth in a partially dentate arch. The patient can remove it from the mouth. • Complete denture: A removable dental prosthesis that replaces the entire dentition and associated structures of the maxilla and mandible.

9. Reasons for tooth loss • Traumatic injuries • Caries • Periodontal diseases • Cysts, malignancies and tumors • Radiation therapy for tumors • Grossly malaligned teeth • Iatrogenic extraction • Congenitally missing teeth • Failure to erupt (impacted teeth)

10. Sequelae of tooth loss • Resorption: The socket gradually remodels until it assumes the shape of the rounded edentulous ridge. • Tilting • Drifting • Occlusal disharmony leads to discomfort, pain, or damage to temporomandibular joints.

11. Sequelae of tooth loss

12. Treatment Options • Preservation and prevention • Post and core/crowns

13. Treatment options • Implants

14. Treatment options Fixed partial dentures

15. Treatment options • Cast Removable partial dentures

16. Treatment options • Overdenture

17. Treatment options • Complete denture

18. Treatment options • Implant retained denture

19. Treatment options • Maxillofacial prostheses Make prosthetic replacements of other areas of the mouth and face lost by disease and trauma

20. Treatment objectives of CD • Patient education • Restoration of esthetics • Improvement of mastication • Improvement of speech • Preservation of remaining oral structures

21. Treatment objectives of CD • Maintenance of the health and comfort of the mouth • Maintenance of the health of the TMJ • General physical and psychological well being of the patient.

22. The residual alveolar ridges Following loss or extraction of teeth: • The empty socket fills with clot and gradually replaced with new bone • The bone around the socket reorganizes • The mucoperiosteum gradually heals & covers the healing socket • The remodelling process results in a rounded ridge like structure known as the residual alveolar ridge ( RAR)

23. The RAR plays a very important role in the construction of the CD

24. Six orders of residual ridge form • Order I Preextraction • Order II Postextraction • Order III High, well rounded • Order IV Knife edge • Order V Low, well rounded • Order VI Depressed

25. Six orders of residual ridge form

26. Rate of resorption • Most rapid in the first 1 year after extraction and can be as high as 4.5 mm / year. • After healing of residual ridge, annual rate of reduction in height is about 0.1-0.2 mm in mandible • Annual rate of reduction in height is about 4X greater in mandible than in maxilla.

27. Pattern of resorption Maxilla The resorption is upwards and inwards (smaller) Mandible The resorption is downward and outward (wider)

28. Masticatory loads • Significantly lower than that produced by natural teeth • Natural teeth can produce forces up to 175 pounds but usually 40 to 50 pounds • Denture wearers: the average force was in the region of 22-24 pounds in the molar-bicuspid region

29. Masticatory loads CD wearers are able to generate forces that are only 10-15% of those with natural teeth

30. Complete Denture Overview

31. Diagnosis and Treatment Plan

32. Tissue Condition Improve Tissue Health

33. Tissue Condition Resilient Liner

34. Preliminary Impressions

35. Pour Diagnostic Casts

36. Make Custom TraysMore Accurate Impressions

37. Border MoldAccurate Registration of Peripheries for Retention

38. Remove Tray Spacer and Load Impression Material

39. Make Final Impression

40. Box ImpressionStronger cast with peripheries for processing

41. Pour Master Casts

42. Record Bases and Occlusion RimsFor Making Jaw Relationship Records

43. Facebow RecordRelates Maxilla to Transverse Hinge Axis

44. Mount Maxillary CastSame Relationship to Transverse Hinge Axis

45. Determine Occlusal Vertical DimensionFacial Height/Separation of Dentures

46. Centric Relation RegistrationAnt/Post & Mediolateral Relationships

47. Mount Mandibular Cast on Articulator

48. Set Anterior and Posterior Teeth in WaxAbility to Visualize and Change Appearance

49. Finalize Waxup

50. Remove Denture from ArticulatorFlask for Processing